A Generalised Multi-Protocol Label Switching (GMPLS) network can comprise circuit-switched networks, e.g. using Synchronous Digital Hierarchy (SDH) or Wavelength Division Multiplexed (WDM) transport equipment, packet-switched networks, e.g. using Ethernet transport equipment, or a mix of circuit-switched and packet-switched networks.
GMPLS networks can be quite dynamic in terms of their topology (e.g. number of nodes, and links between nodes) and the bandwidth available for links. Topology resources of the network are described by Management Information Bases (MIB), defined by the Internet Engineering Task Force (IETF). MIBs are stored at each network node. Two network protocols are used to collect topology information for the MIBs: Open Shortest Path First with Traffic Engineering extensions (OSPF-TE) and Link Management Protocol (LMP). OSPF is a routing protocol and therefore is able to collect network topology information across a wide area. LMP only collects topology information related to the node neighbours. The topology information collected via LMP is more detailed than that collected via OSPF, and includes fine-grained information about service provisioning and topology management in terms of the data plane and the Data Communication Network (DCN). The Data Communication Network comprises a Signalling Communication Network (SCN) and a Management Communication Network (MCN). SCN is the network infrastructure that allows the nodes participating in the control plane to talk to each other to exchange protocol information such as LMP and OSPF-TE. MCN is the infrastructure used by the nodes to send and receive information to/from the network management system, called Operation Systems and Support (OSS). Each network element runs a protocol stack that includes both the OSPF and LMP protocols.
The management system, or Operation Systems and Support (OSS), oversees operation of a GMPLS network. Typically, with conventional GMPLS network management systems, a human operator is required to manually perform node installation and link creation. This is a tedious and error-prone approach. Some enhancements have been implemented in the Ericsson GMPLS OSS application “ServiceOn™”. An example of the current implementation will now be described. Firstly, a human operator can request a topology discovery by selecting the relevant OSPF routing area ID of a routing area and a RouterID (in terms of IP Address) that is part of the selected routing area. The system asks to the specified RouterID the list of the nodes that are advertised in the selected OSPF routing area. This is achieved by OSPF MIB “GET” operations. For each node in the gathered list, the system will use a thread pool to start LMP queries in parallel to obtain the relevant information about: Adjacencies; TE Links and related components; and Control Channels. Information collected using the above method is merged to build an OSS topology model in a database.
The approach described above has a disadvantage of requiring a significant amount of control plane signalling (i.e. OSPF signalling and LMP signalling) within the network, solely to gather the information required for the OSS topology model. This also incurs a processing overhead at nodes of the network and the OSS.